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多孔碳制备过程中,孔结构的发展和石墨化的演变相互依存,且高的石墨化度往往导致孔隙结构衰减。为同时提高煤基多孔碳孔隙结构与石墨化程度,本文以我国大储量准东煤为原料,通过添加FeCl_3实现孔隙结构与石墨化度的协同调控,探究不同FeCl_3添加量的影响。结果表明:随着FeCl_3添加量增加,煤焦比表面积由346 m~2·g~(-1)增加到574m~2·g~(-1);石墨化程度逐渐增加,I_G/I_(All)由8.774%增加到9.328%。通过分析得出:FeCl_3水解及热解作用产生的铁氧化物与热解、活化过程产生的CO反应原位形成CO_2,对煤焦刻蚀,促进微孔的发展;煤焦中无定型碳与还原性Fe形成Fe_3C中间相,在碳不断“溶解析出”过程实现了催化石墨化的进行;酸洗过程释放了一部分中孔。由此可见,FeCl_3同时起着微孔造孔剂、中孔模板剂及催化石墨化促进剂的作用。
During the preparation of porous carbon, the development of pore structure and the evolution of graphitization are interdependent, and the high graphitization degree often leads to the attenuation of pore structure. In order to improve the porosity and graphitization degree of coal-based porous carbon, this paper uses the quasi-Dong coal with large reserves in our country as raw material, through the coordinated adjustment of pore structure and graphitization degree by adding FeCl_3, and explores the effects of different FeCl_3 additions. The results showed that the specific surface area of coal char increased from 346 m 2 · g -1 to 574 m 2 · g -1 with the addition of FeCl 3, the graphitization degree gradually increased, and the ratio of I_G / I_ ) Increased from 8.774% to 9.328%. Through the analysis, the iron oxides produced by the hydrolysis and pyrolysis of FeCl_3 form CO_2 with the CO reaction in the pyrolysis and activation process in situ, which can etch the coal char and promote the development of micropores. The amorphous carbon and Reducing Fe formed Fe_3C mesophase, which catalyzed graphitization in the process of continuous “dissolution of carbon”, and some mesopores were released during pickling. Thus, FeCl_3 plays the role of microporous pore-forming agent, mesoporous template agent and catalytic graphitization promoter.